On product display or storage shelving, such as in supermarkets, warehouses and the like, it is frequently necessary to divide a shelf lengthwise into discrete storage areas for different products. Furthermore, depending on the products to be shelved, it may be necessary from time to time to change the lengths of the respective storage areas. Accordingly, use is made attachable-detachable shelf dividers which can be attached to a shelf at suitable locations to define the respective areas and which can be moved along the shelf, if required, to adjust the lengths of such areas. The invention relates to a shelf divider of this kind.